The ethylenediamine Ru(II) tricarboxyterpyridine complex [Ru(tctpy)(en)(NCS)]Cl (1) was newly synthesized, and its photophysical and photovoltaic properties were characterized. Solar cells based on nanocrystalline TiO2 films sensitized with I exhibited efficient sensitization over the visible and near-infrared region. These solar cells generated a large short-circuit photocurrent of 17.7 mA cm(-2) and an open-circuit potential of 0.68 V under simulated AM 1.5 solar irradiation (100 mW cm(-2)) with a solar energy conversion efficiency of 8.5%.